Cloudflare's DDoS protection is effective for any attack size and any type of attack (Layer3/4, Layer 7 or DNS). We have no attack cap size and do not charge overage fees.
Attack size range from 10 gigabytes per second (Gbps) to over 1 terabyte per second (Tbps). However, we have seen larger attacks. Read more at Famous DDoS Attacks.
In addition, you can read about various case studies:
- How to Launch a 65Gbps DDoS, and How to Stop One
- Ceasefires Don't End Cyberwars
- The DDoS That Almost Broke the Internet
- Reflections on reflection (attacks)
- Stupidly Simple DDoS Protocol (SSDP) generates 100 Gbps DDoS
- Memcrashed - Major amplification attacks from UDP port 11211
- The real cause of large DDoS - IP Spoofing
Cloudflare is designed to mitigate DDoS attacks in a variety of ways. See Protect Against DDoS Attack for a detailed explanation.